A French judge on Friday charged the alleged mastermind of the spectacular Paris heist in which five masked men robbed US reality TV television star Kim Kardashian of jewellery worth millions, prosecutors said.

Sixty-year-old Aomar A. was among six suspects charged on Friday over the October 3 robbery during which the celebrity was bound and gagged at gunpoint, then locked in a bathroom at the luxury residence where she was staying during Paris Fashion Week.

A total of 10 people have now been charged, including five accused of playing a direct role in robbing the 36-year-old Kardashian of jewellery worth some nine million euros ($9.5 million).

Sources close to the probe said the BRB special police unit in charge of armed robberies began watching Aomar A. -- who was sentenced to seven years in prison for armed robbery in 1985 -- after finding his DNA at the scene on materials used to tie up Kardashian.

One of the alleged robbers was named Friday as Didier D., aged 61 and nicknamed "Blue Eyes," the prosecutors said.

He was sentenced in 2003 to eight and half years in jail for international cocaine trafficking after being busted with two tonnes of the drug at a Paris airport.

The surveillance soon led police to the other suspects, and on Monday, the BRB launched a series of coordinated raids in the Paris area and in southern France during which they rounded up 17 people.

A Paris prosecutor on Friday praised the BRB's "remarkable work".

A source close to the probe said some of the suspects have confessed to their involvement, but would not say which ones.

The five alleged assailants, who range in age from 54 to 72, have been described as "old-school gangsters".

Wearing police uniforms, gunmen first overpowered a night watchman at the residence in the chic Madeleine area of the French capital where the US celebrity was staying.

Two of them -- Aomar A. and "Blue Eyes", police think -- then burst into the star's apartment, gagged and bound her and locked her in a bathroom before helping themselves to gems including a 20-carat Lorraine Schwartz diamond ring worth some four million euros.

It was the biggest jewellery theft from an individual that France has seen in more than 20 years.

The oldest of the suspected burglars is 72-year-old Pierre "Pierrot" B., a convicted cocaine dealer who was sentenced to six years in jail. He was arrested in a villa in the south of France on Monday.

The ringleader's 70-year-old companion, named as Christiane G., and his 29-year-old son Harminy A. were charged with abetting the crime, with the son suspected of driving the thieves to the scene.

- Trail led to Antwerp -

Marceau B., a 64-year-old Roma, was charged with helping to pass off some of the stolen jewellery.

He has a long criminal record dating back to 1998, with convictions for robbery and carrying counterfeit cash. Six months after leaving jail in late 2011, he was charged with making counterfeit money but was acquitted last year.

Investigators believe they spotted Marceau B. in Antwerp, Belgium, the hub of the global diamond trade.

They fear some of Kardashian's jewels have already been sold, as raids against suspects have turned up 200,000 euros in cash.

The diamond ring, much photographed and easily recognisable, would be especially difficult to pass off, experts say.

Such gems are often recut into smaller stones, and police say Kardashian's ring could lose three-quarters of its value after being reworked.

Seven suspects have been released from custody including a chauffeur who was used by Kardashian during her stay.

His 27-year-old brother, Gary M., was charged Friday on suspicion of tipping off the thieves that Kardashian's bodyguard was absent on the night of the robbery and giving them details about the residence.

The bodyguard, who was providing security for her sister Kourtney at a Paris nightclub at the time, no longer works for the family.